Chimney Lightning Strike

[fireinvest123]

Hi I recently read a post concerning lightning strikes. I am a retired fire investigator. I will be traveling out of town to examining a house fire soon. The opposing parties are claiming that lightning struck a chimney and transferred the charge to the gas supply lines of a fireplace and initiated a fire. NFPA 78 seems to be unclear about gas lines being grounded as this may cause more problems that it would solve. What is the proper manner to bond the gas lines. I was contacted by a representative the gas line installer.

 

[dereckbc]

Re: Chimney Lightning Strike

Refer to NEC 250.104(B). metal piping system(s) including gas piping, that may become energized shall be bonded to the service equipment enclosure.

The gray area IMO was the pipe likely to be become enrgized by the electrical system. The requirement is not for lightning protection, only electrical protection.

 

[jtester]

Re: Chimney Lightning Strike

In 1987 and earlier, gas piping was used as a grounding electrode, and when permitted by the gas company was connected at each electric service to the electrical system ground. I think it was dropped in the 1990 edition. I don't know if it was common in 1987, but when I worked for utilities in the 1970's it was quite common where I worked.
Jim T